strago: Add null terminator at end of platform names list

CL:3668342 accidentally deleted the null terminator at the end of this
list, generally causing a segfault. Add it back.

BUG=b:234397226
TEST="mosys platform name" on caroline reports "Caroline"

Change-Id: If264d86b72ce8021674e32d861e764130f6e1b56
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/mosys/+/3680761
Auto-Submit: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: Alexander Liu <alexanderliu@google.com>
Tested-by: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Alexander Liu <alexanderliu@google.com>
diff --git a/platform/x86_64/strago/strago.c b/platform/x86_64/strago/strago.c
index 69d42b7..bcf0b6d 100644
--- a/platform/x86_64/strago/strago.c
+++ b/platform/x86_64/strago/strago.c
@@ -58,6 +58,7 @@
 	"Ultima",
 	"Umaro",
 	"Wizpig",
+	NULL,
 };
 
 static struct platform_cmd *strago_sub[] = {